A conventional image processing apparatus detects whether a target pixel constitutes a black edge and detects whether the target pixel constitutes a white edge. A black edge is detected when the target pixel is a black pixel and the density at the border with peripheral pixels changes from white to black. A white edge is detected when the target pixel is a white pixel and the density at the border with peripheral pixels changes from black to white. The image processing apparatus changes the multiple value representing the target pixel to their maximum level (level representing pure black) when the target pixel constitutes a black edge, and changes the multiple value representing the target pixel to their minimum level (level representing pure white) when the target pixel constitutes a white edge. This image process is thought to be capable of achieving suitable edge enhancement.